The panel of five experts says the U.S. Fish and Wildlife Service didn't use the best available science when it proposed dropping protection for gray wolves. The panel was unanimous in its conclusion that the federal government relied too heavily on a paper on species classification that is not universally accepted.

The peer review bolsters environmental groups, who have argued it's premature to declare the gray wolf population recovered.

“We believe that means it's time to table this delisting proposal and go back and find a better plan for managing wolves across the nation,” says Suzanne Stone, who works out of Idaho for the Defenders of Wildlife.

Several scientists on the panel noted that the Northwest historically had a distinct population of coastal wolves, which are just now starting to return.

The U.S. Fish and Wildlife Service has re-opened the public comment period on its proposal for an additional 45 days.